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Biomedical subjects

M J Miller

Publications and source records attributed to M J Miller.

At least 37 records · Page 2Linked to original sources
PubMed2001

The adsorption of cyanobacterial hepatotoxins from water onto soil during batch experiments.

Public health concerns associated with cyanobacteria, both chronic and acute, arise from their ability to produce toxins. Rural communities within Australia and those in developing countries require an inexpensive and low-cost method for removing toxins from drinking water. A candidate technology is bank filtration. Adsorption of cyanobacterial hepatotoxins was measured in batch studies to determine the applicability of bank filtration as an efficient removal strategy. Five soils with different physicochemical properties were collected from regions around South Australia. The soils were mixed with either nodularin or microcystin-LR in distilled water and buffered solutions (pH 4.8, 6.9 and 9.1). Additionally, nodularin was mixed in unbuffered solutions (pH 4.8 and 8.9). The three soils with the high clay and/or organic carbon contents (Paringa A, McLaren Flat and Lakes Plains) had the higher nodularin adsorption coefficients, ranging from 0.2 to 16.59 L kg-1. Soil suspensions in acetate buffer (pH 4.8) generally produced significantly higher nodularin adsorption coefficients, when compared to the other buffer systems. The background interference from the ionic strength of the buffers, however, made interpretation of the effect of pH on toxin sorption difficult. Increases in solution ionic strength, from freshwater to seawater, resulted in corresponding increases in the nodularin adsorption coefficients for all sites, except the sandy Hallett Cove site. The implications for bank filtration are that higher water pH values and lower salinities will enhance the in situ mobility of the toxins, resulting in an increased distance of filtration through the river bank before toxin free water could be abstracted for human consumption.

Adsorption↗
PubMed2001

Exposure of migrant bald eagles to lead in prairie Canada.

The prevalence of elevated exposure to lead was assessed in a migrant population of bald eagles (Haliaeetus leucocephalus) at a waterfowl staging area in the southern portion of the Canadian prairies, from September to November, 1992-1995. Of 103 eagles, 8% exhibited blood lead (PbB) concentrations suggestive of elevated exposure to lead (> or = 0.200 microgram ml-1 wet wt.). PbB concentrations in eagles from the study area ranged from < 0.01 to 0.585 microgram ml-1, while those of nestling eagles from a reference site indicated normal or background exposure (< 0.01 microgram ml-1). No differences in the prevalence of elevated exposure were detected among genders or age classes (0.5- and > or = 1.5-year-old birds) (P > 0.05). The prevalence of elevated exposure was significantly greater in November than in October (21.7 vs. 3.8%) (all years: chi 2Y = 5.75, P = 0.017). Eagles with shotshell pellets in the digestive tract did not have accompanying high PbB concentrations. The prevalence of elevated lead exposure in this study was low in comparison to other areas in North America. Potential biases in the trapping technique as they relate to interpreting the results are addressed.

Animals↗
PubMed2001

The remarkable hydrophobic effect of a fatty acid side chain on the microbial growth promoting activity of a synthetic siderophore.

The ability of synthetic derivatives of the siderophore tripeptide of N5-hydroxy-N5-acetyl-L-ornithine to promote the growth of various strains of mycobacteria and Gram negative bacteria was found to depend significantly on the hydrophobic nature of the derivative. Although the tripeptide of N5-hydroxy-N5-acetyl-L-ornithine is not normally utilized by mycobacteria, an N-terminal palmitoyl derivative mimicked natural mycobactin J in all studies.

Bacteria↗
PubMed2001

Inhibition of neurogenic inflammation by the Amazonian herbal medicine sangre de grado.

UNLABELLED: This study was designed to determine if the Amazonian medicinal sangre de grado, confers benefit by suppressing the activation of sensory afferent nerves. METHODS: (i) vasorelaxation of rat mesenteric arteries in response to calcitonin gene-related peptide; (ii) rat paw edema in response to protease- activating peptide receptor 2-activating peptide; (iii) rat paw hyperalgesia in response to low-dose protease-activating peptide receptor 2-activating peptide or prostaglandin E2; (iv) gastric hyperemia in response luminal capsaicin; (v) a clinical trial of a sangre de grado balm in pest control workers. The parent botanical was fractionated for evaluation of potential active components. In preconstricted rat mesenteric arteries, highly diluted sangre de grado (1:10,000) caused a shift to the right of the calcitonin gene-related peptide dose-response curve (p < 0.01). Paw edema in response to protease-activating peptide receptor 2-activating peptide (500 microg) was reduced by as single topical administration sangre de grado balm (1% concentration, p < 0.01) for at least 6 h. Hyperalgesia induced by either low-dose protease-activating peptide receptor 2-activating peptide (50 microg) or prostaglandin E2 was prevented by sangre de grado balm. A fraction possessing analgesic and capsaicin antagonistic properties was isolated and high-performance liquid chromatography and gas chromatography-mass spectrometry analysis indicated that it was a proanthocyandin oligomer. In pest control workers, sangre de grado balm (Zangrado) was preferred over placebo, for the relief of itching, pain, discomfort, edema, and redness in response to wasps, fire ants, mosquitoes, bees, cuts, abrasions, and plant reactions. Subjects reported relief within minutes. We conclude that sangre de grado is a potent inhibitor of sensory afferent nerve mechanisms and supports its ethnomedical use for disorders characterized by neurogenic inflammation.

Animals↗
PubMed2001

Indications for immediate tissue transfer for soft tissue reconstruction in visceral pelvic surgery.

BACKGROUND: Perineal wound complications may occur after visceral pelvic surgery. We reviewed our experience to determine indications for immediate tissue transfer (TT) to prevent complications. METHODS: Hospital records and computerized data were reviewed on 175 perineal repairs in 156 patients treated at The University of Texas M.D. Anderson Cancer Center for tumors involving the alimentary tract (135 of 175), genitourinary tract (15 of 175), perineum (19 of 175), or sacrum (6 of 175). Patients had either resection of only the colorectum and anus (APR) (46 of 175) or multivisceral resection (MVR) (129 of 175), and the perineal wound was closed by using TT (108 of 175) or primary closure (PC) (67 of 175) on the basis of the surgeon's judgment. Complications were compared between PC and TT groups. RESULTS: Complications occurred in 57% (100 of 175). There was no significant difference overall in PC and TT procedures or in the APR subgroup. There were significantly fewer complications for TT patients in the MVR subgroup (P =.0001). There were significantly fewer complications for TT patients with prior irradiation in both APR (P =.01) and MVR (P =.007) subgroups. CONCLUSIONS: Immediate TT for perineal wound closure is associated with fewer healing complications than PC in a subset of patients with multivisceral resection or prior radiotherapy. Surgical planning in these cases should consider immediate soft tissue reconstruction.

Adult↗
PubMed2001

Thrombolytic therapy: what is its role in free flap salvage?

Thrombolytic agents have been demonstrated to improve free flap salvage in animal models. However, clinical evidence regarding their efficacy has been scant. The authors reviewed their experience with flap salvage using thrombolytic therapy in 1,733 free flaps from February 1990 to July 1998. Patients with intraoperative pedicle thrombosis were excluded from this review. Forty-one of the 55 free flaps that were reexplored emergently were identified as having pedicle thrombosis. Of these 41 flaps, 28 free flaps were salvaged (flap salvage group, 68%) and 13 free flaps failed (flap failure group, 32%). Thrombolytic therapy (urokinase in 7 patients, tissue plasminogen activator in 1 patient) was used in six flaps in the flap salvage group and two flaps in the flap failure group. Statistical analysis demonstrated no difference between the two groups with regard to thrombolytic therapy. There was also no difference between the two groups with regard to use of systemic heparin (100-500 U per hour) at the time of pedicle thrombosis or with regard to whether Fogarty catheters were used. Smoking, preoperative radiotherapy, and the use of interpositional vein grafts during initial flap reconstruction had no impact on the outcome of flap salvage. The flap salvage group was reexplored at a mean of 1.5 days compared with the flap failure group, which was reexplored at a mean of 4.2 days (p = 0.007). Early detection of pedicle thrombosis remains the most important factor in the salvage of free flaps. Although these numbers are small and definitive statements cannot be made, the role of thrombolytic agents in free flap salvage requires further clinical evaluation.

Fibrinolytic Agents↗
PubMed2001

Comparison of cost for DIEP and free TRAM flap breast reconstructions.

A recent article by Kaplan and Allen suggested that deep inferior epigastric perforator (DIEP) flap breast reconstruction was less expensive than reconstruction performed with free transverse rectus abdominis musculocutaneous (TRAM) flaps. To test that hypothesis, a series of patients who had undergone unilateral breast-mound reconstruction by the first author using DIEP or free TRAM flaps between November 1, 1996, and March 30, 2000, were reviewed. Bilateral reconstructions and reconstructions performed by other surgeons in the department were excluded to eliminate all variables except the choice of flap. All hours in the operating room and days in the hospital until discharge were included. Early readmissions for the treatment of complications were included, as were the costs of the mastectomy in the case of immediate reconstructions, but late revisions and nipple reconstructions were not. The totals were then converted into resource costs in 1999 dollars, and the DIEP and free TRAM flap groups compared. There were 21 DIEP flaps and 24 free TRAM flaps in the series. In this series, there was no significant difference between the cost of DIEP and free TRAM flap breast reconstruction.

Breast Neoplasms↗
PubMed2001

Web-based medicine as a means to establish centers of surgical excellence in the developing world.

The growth of the Internet has provided a unique opportunity for rapid, global communication. Web-based medicine uses this technology to help surgeons in developing regions of the world gain direct access to recognized experts. This serves to empower local surgeons in the developing world through direct skill-transfer and encouraging academic pursuit. Web-based medicine follows the paradigm of a university without borders, therefore requiring exacting patient record keeping, monthly peer review, and continuing medical education of all its participants. All those who participate in Web-based medicine have undergone a credentialing process to guarantee that they possess adequate credentials. Patient confidentiality is strictly maintained. Web-based medicine also provides a follow-up strategy for medical volunteer groups who provide overseas services. Interplast, Inc., has administered a Web-based medicine site at http://www.wiredmd.com since July of 1999. A total of 767 cleft malformation cases performed locally by participating host surgeons in the developing world have been reviewed through the site. Additionally, 16 consultations have been posted and discussed by participating surgeons worldwide. Financing remains the major impediment to the globalization of this technology.

Cleft Lip↗
PubMed2001

Direct correlation between diffusion of Loxosceles reclusa venom and extent of dermal inflammation.

OBJECTIVES: Envenomation by Loxosceles species (brown recluse) spiders results in large dermal inflammatory lesions. Venom-induced dermal inflammation occurs indirectly via soluble mediators of inflammation. This study aimed to explore whether the anatomic extent of dermonecrotic arachnidism is due to the cascade of soluble proinflammatory mediators elicited by venom deposited at the bite site, or due to diffusion of the venom per se. METHODS: Three New Zealand white rabbits received intradermal L. reclusa venom (3-microg) injections in the flank. At the time of maximum dermal inflammation (24 hr), paired 4-mm dermal biopsies were obtained in 2-cm intervals extending 0 to 12 cm from the inoculation site. Normal dermal tissue was obtained from the opposite flank to serve as a negative control. One biopsy sample from each interval was homogenized and assayed for myeloperoxidase (MPO) activity and for the presence of venom via an enzyme immunoassay (EIA). The other paired dermal biopsy was sectioned, and examined for the presence of polymorphonuclear neutrophils (PMNs) by microscopy. Lesional areas were measured using digital images imported into imaging software. RESULTS: Mean +/- SD lesional diameter 24 hours post inoculation measured 9.18 +/- 0.64 cm. Venom was detected in biopsies 0 to 10 cm from the injection site. As expected, the highest venom concentrations were measured at the inoculation site (4.28 +/- 3.9 ng/4 mm). In addition, PMNs and MPO were detected up to 8 and 10 cm from the inoculation site, respectively. Neither PMNs nor MPO was detected in tissue absent of venom (kappa = 0.88, p < 0.001). CONCLUSIONS: Loxosceles venom diffuses from the envenomation site. The extent of dermal inflammation mirrors the extent of Loxosceles venom diffusion. This observation implies that the venom itself defines the extent and magnitude of tissue injury following Loxosceles envenomation.

Animals↗
PubMed2001

Increased nitrite and nitrate concentrations in sera and urine of patients with cholera or shigellosis.

OBJECTIVES: Nitric oxide (NO) is an important regulator of cell function. In the intestine, NO regulates blood flow, peristalsis, secretion, and is associated with inflammation and tissue injury. The objectives of this study were to assess and compare the role of NO in cholera, a noninflammatory enteric infection, and in shigellosis, a bacterial inflammation of the colon. METHODS: We determined serum and urinary concentrations of nitrite and nitrate during acute illness and early convalescence in 45 hospitalized children: 24 with cholera and 21 with shigellosis; 18 healthy children served as controls. Nitrite and nitrate concentrations were determined spectrophotometrically using Greiss reaction-dependent enzyme assay. RESULTS: Serum nitrite and nitrate concentrations were significantly (p < 0.05) increased during acute illness compared to the early convalescence in both cholera and shigellosis. Urinary nitrite and nitrate excretions were significantly (p < 0.01) increased during acute disease in shigellosis, but not in cholera. Nitrite concentrations correlated with stool volume (r2 = 0.851) in cholera and with leukocytosis (r2 = 0.923) in shigellosis. CONCLUSIONS: Both cholera and shigellosis are associated with increased production of NO, suggesting its pathophysiologic roles in these diseases.

Acute Disease↗
PubMed2001

Cardiorespiratory events in preterm infants referred for apnea monitoring studies.

BACKGROUND: Episodes of apnea, desaturation, and bradycardia are common in preterm infants. Such infants who have persistent cardiorespiratory events detected by clinical bedside monitoring often are referred for overnight apnea monitoring studies. OBJECTIVE: To characterize apnea, bradycardia, and desaturation events in infants referred for an overnight apnea monitoring study and compare them with corresponding events in control infants of similar age and weight with no bedside monitor alarms. METHODS: Twelve-hour bedside apnea monitoring studies were performed on 68 preterm infants before hospital discharge. This population included 35 infants who were referred by their attending physicians because of persistent bedside monitor alarms (referral group) and 33 infants who had no documented cardiorespiratory events for at least 2 days before the study (control group). Each study monitored respiration via respiratory inductance plethysmography, oxygen saturation (Sao2), and heart rate. Events were defined as meeting 1 of the following criteria: apnea > or =20 seconds, bradycardia < or =80 beats per minute, or Sao2 < or =80%. RESULTS: The incidence of apnea > or =20 seconds was low, with no significant difference between infant groups. Referral infants exhibited a higher occurrence of desaturation episodes (20 +/- 6 vs 6 +/- 3 episodes/12-hour study) and a higher occurrence of bradycardia episodes (4.3 +/- 0.8 vs 1.1 +/- 0.3 episodes/12-hour study) than controls. These episodes of desaturation and bradycardia were always preceded by a respiratory pause, which was shorter in the referral infants (10.0 +/- 0.4 seconds vs 12.0 +/- 1.0 seconds). Baseline Sao2 was lower in referrals than controls (95 +/- 1% vs 98 +/- 1%), and the incidence of periodic breathing was significantly higher. CONCLUSIONS: Infants referred for apnea monitoring studies because of persistent bedside monitor alarms have very infrequent prolonged apnea but a higher frequency of desaturation and bradycardia in response to short respiratory pauses than infants without persistent bedside monitor alarms. Referral infants also exhibit a lower baseline Sao2. These abnormalities in oxygenation and cardiorespiratory control may be markers for subtle residual lung disease or functional central nervous system abnormalities.

Apnea↗
PubMed2001

Three-dimensional microscopic image reconstruction of prostatic adenocarcinoma.

CONTEXT: Routine microscopy provides only a 2-dimensional view of the complex 3-dimensional structure that makes up human tissue. Three-dimensional microscopic image reconstruction has not been described previously for prostate cancer. OBJECTIVES: To develop a simple method of computerized 3-dimensional image reconstruction and to demonstrate its applicability to the study of prostatic adenocarcinoma. METHODS: Serial sections were cut from archival paraffin-embedded prostate specimens, immunostained using antikeratin CAM5.2, and digitally imaged. Computer image-rendering software was used to produce 3-dimensional image reconstructions of prostate cancer of varying Gleason grades, normal prostate, and prostatic intraepithelial neoplasia. RESULTS: The rendering system proved easy to use and provided good-quality 3-dimensional images of most specimens. Normal prostate glands formed irregular fusiform structures branching off central tubular ducts. Prostatic intraepithelial neoplasia showed external contours similar to those of normal glands, but with a markedly complex internal arrangement of branching lumens. Gleason grade 3 carcinoma was found to consist of a complex array of interconnecting tubules rather than the apparently separate glands seen in 2 dimensions on routine light microscopy. Gleason grade 4 carcinoma demonstrated a characteristic form of glandular fusion that was readily visualized by optically sectioning and rotating the reconstructed images. CONCLUSIONS: Computerized 3-dimensional microscopic imaging holds great promise as an investigational tool. By revealing the structural relationships of the various Gleason grades of prostate cancer, this method could be used to refine diagnostic and grading criteria for this common tumor.

Adenocarcinoma↗
PubMed2001

Hemograms for and nutritional condition of migrant bald eagles tested for exposure to lead.

Plasma proteins, hematocrit, differential blood counts were examined and nutritional condition was estimated for bald eagles (Haliaeetus leucocephalus) trapped (n = 66) during antumn migration, 1994-95 at Galloway Bay (Saskatchewan, Canada), for the purposes of estimating prevalence of exposure to lead. Sex and age differences in hematocrit and plasma proteins were not observed; however, female eagles exhibited larger median absolute heterophil counts than males. Hematologic values were similar to those previously reported from eagles in captivity. Departures from expected hematological values from a healthy population of eagles were not observed in birds with elevated levels of blood lead (> or =0.200 microg/ml). Similarly, nutritional condition was not related to blood-lead concentrations. Therefore, it appears that lead exposure in this population was below a threshold required to indicate toxicological alteration in the hematological values and index of nutritional condition that we measured.

Age Factors↗
PubMed2001

Disinfection efficacy of contact lens care solutions against ocular pathogens.

PURPOSE: Three commercially available products labeled as multi-purpose contact lens solutions, one multi-purpose disinfecting solution, and a hydrogen peroxide system were evaluated for antimicrobial activity according to the current International Organization for Standardization (ISO) and the U.S. Food and Drug Administration (FDA) stand-alone procedure for disinfecting products. One multi-purpose solution was selected to assess its antimicrobial activity against two human corneal isolates of Pseudomonas aeruginosa. METHODS: Products were challenged with bacteria and fungi, and following a specified period, aliquots of inoculated test solution were neutralized and plated on validated recovery media. After incubation the number of viable microorganisms was enumerated and mean log reductions determined. RESULTS: ReNu MultiPlus (Bausch & Lomb, Rochester, NY), AOSEPT (CIBA Vision Corporation, Duluth, GA), and Opti-Free Express with Aldox (Alcon Laboratories, Ft. Worth, TX) were the only lens care products that met the stand-alone criteria for all required microorganisms within their minimum recommended disinfection time. Of these, ReNu MultiPlus provided the greatest overall antimicrobial activity. ReNu MultiPlus demonstrated a significantly higher mean log reduction of Staphylococcus aureus and Serratia marcescens than Opti-Free Express. ReNu MultiPlus also gave a higher mean log reduction of S. aureus and S. marcescens than AOSEPT, and a higher mean log reduction of Candida albicans and Fusarium solani than AOSEPT, Complete Comfort Plus (Allergan, Irivine, CA), and Solo-Care (CIBA Vision Corp.) (at 4 hours). Both Complete Comfort Plus and Solo-Care (at 4 hours) met the primary acceptance criteria for bacteria; however, neither product possessed enough antimicrobial activity to meet the minimum criteria for yeast or mold. ReNu Multiplus was effective against corneal isolates of P. aeruginosa. CONCLUSION: ReNu MultiPlus, AOSEPT, and Opti-Free Express met the requirements of the stand-alone primary criteria for disinfecting solutions. ReNu MultiPlus demonstrated the greatest overall disinfection efficacy, as well as excellent activity against clinical strains of P. aeruginosa.

Anti-Bacterial Agents↗
PubMed2001

Multidisciplinary care in head and neck cancer.

Head and neck cancer treatment is uniquely suited to multidisciplinary care. A comprehensive list of essential participants consists of a broad spectrum of health care professionals. A spirit of cooperation and mutual respect is the foundation for the synergy that results in the best possible patient care. Reconstructive surgery has emerged as a sophisticated subspecialty that fills a critical role restoring the head and neck patient to maximal health and well-being. The concept of multidisciplinary care, pioneered at the nation's comprehensive cancer centers, should be adopted universally by clinicians seeking to offer the patient with head and neck cancer the best care.

Head and Neck Neoplasms↗